1. Field of the Invention
The present application relates to a luminous flux control member, a light-emitting unit, and a display device.
2. Discussion of Related Art
A liquid crystal display (LCD) is a device that changes a variety of electrical information, which has been generated by various devices, to visual information using a variation in liquid crystal transmittance depending on an applied voltage and transmits the visual information. The liquid crystal display has no light-emitting capability and thus requires a back light, but has small power consumption and can be embodied in a small weight and small thickness. Accordingly, the liquid crystal display is widely used.
The liquid crystal display has no light-emitting capability and thus has a backlight unit (BLU) as a light-emitting unit that provides light to a rear surface of a liquid crystal panel on which an image is displayed.
The liquid crystal display includes a liquid crystal panel having a color filter substrate and an array substrate which are separated from each other with a predetermined gap therebetween and which face each other and a liquid crystal layer interposed between the color filter substrate and the array substrate and a backlight unit that irradiates the liquid crystal panel with light.
The backlight unit used in the liquid crystal display can be classified into an edge type and a direct type depending on the positions of light-emitting diodes as light sources.
In an edge type backlight unit, light-emitting diodes as light sources are arranged on a side surface of a light guide plate and the light guide plate applies light emitted from the light-emitting diodes to the liquid crystal panel using total reflection and the like.
In a direct type backlight unit, a diffusing plate is used instead of the light guide plate and light-emitting diodes are arranged on the rear surface of the liquid crystal panel. Accordingly, the light-emitting diodes apply light to the rear surface of the liquid crystal panel.
On the other hand, illuminance uniformity in a liquid crystal display is an important factor for determining quality of the liquid crystal display. The backlight unit has to uniformly apply light to the liquid crystal panel.